Jailed blogger Raif Badawi sent his message on the fifth day of violent anti-government protests in Iran.

Saudi prisoner Raif Badawi has urged Iranian revolutionaries to "not forget the prisoners of free speech such as Nazanin Zaghari-Ratcliffe, Mohammed Ali Taheri and many others" after violent protests broke out in Iran.

At least 22 people have been killed in violent clashes with security forces since Thursday (28 December). The anti-government protests across Iran are the largest since the disputed presidential election in 2009.

President Hassan Rouhani vowed to crack down on "law breakers."

Badawi, who was jailed in Saudi Arabia for "insulting Islam" in 2012, congratulated "the brave revolutionaries" and called on them to remember the human rights activists imprisoned in Iran in a tweet sent on New Year's Day.

"My husband #RaifBadawi sends his honest greeting from prison to the brave revolutionaries in Iran, and he reminds them not to forget the prisoners of free speech such as Nazanin Zaghari, Mohammad Ali Taheri and many others. #IranProtest," a message on the jailed blogger's Twitter page read.

British-Iranian mother Nazanin Zaghari-Ratcliffe has been detained in a prison in Tehran since April 2016. She was sentenced to five years after a court accused her of plotting to overthrow the Iranian government.

Senior Iranian cleric Ayatollah Ahmad Alamolhoda described her as a "dirty spy."

Saudi Arabia is one of the most tightly controlled media environments in the world. It is ranked 168th of 180 countries in the 2017 World Press Freedom Index, having fallen three places in the last year. Iran was ranked 165th last year, having moved up four places since 2016.

Imprisoned Saudi blogger Raif Badawi has called on Iranian free speech revolutionaries to remember imprisoned activists, such as Nazanin Zaghari-Ratcliffe.

My husband #RaifBadawi send his honest greeting from prison to the brave revolutionaries in Iran, and he reminds them not to forget the prisoners of free speech such as Nazanin Zaghari, Mohammad Ali Taheri and many others.#IranProtest